The change in this quantity when a substance changes temperature is found by using Kirchoff's law.  In only the case when boiling points are known, Trouton's rule can be used to find this quantity for a liquid.  The derivative of Gibbs free energy over temperature with respect to temperature  is equal to the negative change in this quantity over temperature squared according to the Gibbs-Helmholtz equation. This quantity may be summed for individual reactions to find its value for the overall reaction according to Hess's law. At constant pressure, the derivative of thi
The change in this quantity when a substance changes temperature is found by using Kirchoff's law.  In only the case when boiling points are known, Trouton's rule can be used to find this quantity for a liquid.  The derivative of Gibbs free energy over temperature with respect to temperature  is equal to the negative change in this quantity over temperature squared according to the Gibbs-Helmholtz equation. This quantity may be summed for individual reactions to find its value for the overall reaction according to Hess's law. At constant pressure, the derivative of this quantity with respect to temperature is the heat capacity. For ten points, name this quantity equal to internal energy plus pressure times volume, often symbolized H.
The change in this quantity when a substance changes temperature is found by using Kirchoff's law.  
{Enthalpy} (prompt on H before mentioned)